Each WCF message may contain more data than the receiver has expected.
This normally happens when the senders version is newer than the receivers version.
Some data cannot be deserialized at the receiver. WCF provides this object to store this extension data.
When serializing this message again (gateway functionality) the extension data is included and not lost.
IExtensibleDataObject.ExtensionData
WcfMessage Class | SourceForge.AsyncWcfLib Namespace